A coupler is one of the important parts of a railway vehicle, and two cars of the railway vehicle are connected with each other via the coupler. For avoiding a rigid impact between two couplers in the accelerating or decelerating process of the cars, a coupler buffer is mounted to the car according to the conventional technology. The coupler is connected to the car via the coupler buffer which provides buffering.
The coupler buffer in the conventional technology generally is a one-way buffer structure. Reference is made to FIG. 1, which is a schematic view showing the structure of a coupler buffer in the conventional technology.
A conventional coupler buffer includes a follower 2, an elastic component 3, a rear follower stop 4, a coupler yoke 5 and a front follower stop 6. In a case that a car suffers a compression load, for example when a train decelerates, a longitudinal load of the train is transmitted to the follower 2, then to the buffer 3, and finally to the rear follower stop 4 from a coupler 1. The buffer component can buffer the external impact, thereby protecting components which directly suffer a rigid load, such as a coupler body, a coupler knuckle, a coupler yoke, a vehicle body, and cargoes, etc.
In a case that the car suffers a tensile load, for example, when the train accelerates, the longitudinal load of the train is transmitted to the coupler yoke 5, then to the buffer 3, and then to the follower 2, and finally to the front follower stop 6 from the coupler 1. Since the buffer 3 currently used is a dry friction buffer and the quasi-static rigidity of the buffer is great, the buffer 3 cannot function well when a traction force is small, and the coupler body, and the coupler knuckle, the coupler yoke suffer the rigid load directly, thus aggravating the fatigue damage.
Furthermore, the buffer 3 is generally an elastic component. In a case that the vehicle suffers a tensile load, the elastic component 3 and the follower 2 are compressed inbetween the coupler yoke 5 and the front follower stop 6. Thus, when the tensile load suffered by the vehicle excesses the ultimate load of the elastic buffer, the elastic component 3 is apt to be damaged due to being over compressed.
In addition, in a case that the compression load suffered by the vehicle excesses the ultimate load of the buffer, the follower would be further compressed by the coupler until the follower comes into contact with a casing of the buffer. The casing of the buffer plays a role of overload protection, thus avoiding the damage to the coupler door due to a direct contacting of the coupler shoulder and the coupler door for an excessive compression of the buffer in the compression stroke. However, since the compression load is excessive, the casing of the buffer in the conventional technology is apt to be damaged.
Reference is further made to FIG. 2, which is a schematic view showing the structure of another coupler buffer in the conventional technology.
In the coupler buffer in the conventional technology, the coupler 1 of the coupler buffer is connected in the coupler yoke 3 via a coupler tail pin 2. A rotating sleeve 4 is provided between the coupler tail pin 2 and the coupler yoke 3, and is rotatably arranged in the coupler yoke 3. Thus, the coupler 1 can be rotated about its axis via the rotating sleeve 4.
However, in a case that the vehicle is under a compression force, for example, when the railway vehicle accelerates, the rotating sleeve 4 is moved in the direction of the axial compression force under an axial compression force by the coupler tail pin 2. The contact between the coupler yoke 3 and the rotating sleeve 4 is an arc surface contact, and the friction between the coupler yoke 3 and the rotating sleeve 4 is relatively large, which is apt to cause a friction problem between the coupler yoke 3 and the rotating sleeve 4.
Therefore, a significant technical issue to be solved by the skilled person in the art is to provide a coupler buffer which may function well when a vehicle suffers a tensile load, thus avoiding a coupler body, a coupler knuckle and a coupler yoke of the vehicle directly suffering a rigid load, not aggravating the fatigue damage.